Magnetic tape is commonly used for storage of digital data. The magnetic tape is spooled on reels in a cartridge that is insertable into a digital data transfer apparatus in which data can be written onto the tape and/or data can be read from the tape. Such data transfer apparatus, which may be referred to as a tape drives, typically includes a tape head for one or both of reading and/or writing data from or to the tape head.
Known tape drives are generally designed to use a predetermined size tape cartridge that contains tape having a known width. Known cartridge loading devices of tape drives are generally designed to be used with a particular size of cartridge. Such devices conventionally include means for ensuring that only cartridges of the correct size can be inserted and then only when the cartridge is correctly oriented. A feature of known cartridge loading devices is that they are made rigid so that cartridges of the wrong size or incorrectly oriented cartridges cannot be forced into the tape drive, except by the exertion of an unnatural amount of force.
One format for data storage in a helical scan tape drive is Digital Data Storage (DDS). Various versions of DDS exist, but each version uses the same width tape in Digital Audio (DAT) cartridges, including DAT72 and DAT160. The tape width is approximately 4 mm. There is a demand for more and more data storage capacity. This has, to some extent, been met by improved reading and writing techniques that have allowed increased amounts of data to be stored, without changing the tape length or width. However, ultimately, the storage capacity of a given size of tape has a limit.
One solution to the problem of data storage capacity is to increase the width of the tape. Of course, a greater width provides more storage capacity. However, since the cartridge loading devices of tape drives are designed to accept a particular size cartridge, if wider tapes are used, tape drives with loading devices able to accept a larger cartridge must be provided. This then provides the user with the problem that legacy format tape cartridges would not be usable with the new tape drive and so it would be necessary to maintain more than one tape drive or transfer existing stored data to the wider tape.
Conventional cartridge loading devices that can only accept a single size of cartridge are designed in such a way that cartridges can only be inserted when correctly oriented. To this end, conventional cartridge loading devices are of rigid construction and equipped with means, such as ramps or ribs, that interact with formations on the cartridge to prevent insertion in any but the correct orientation. The result is that an incorrectly oriented cartridge can only be inserted by using an unnaturally large force, usually such as would result in damage to the device and/or cartridge.
The applicant is proposing a new cartridge loading device that can expand in such a way that it can accept different sized cartridges. By this means, a single device can be used with tapes having different widths. In such a cartridge loading device, it remains desirable to have means for preventing the insertion of incorrectly oriented cartridges. However, the conventional means rely on the rigidity of the cartridge loading device.
A further factor affecting the design of cartridge loading devices, and in particular the applicant's proposed expanding cartridge loading device, is the so-called form factor. The form factor determines the size of box, or housing, the tape drive can be housed in if it is to be received in the standard sized compartments and openings to be found in computer equipment and the like. If a cartridge loading device that is expandable to receive larger size cartridges is to be widely used, it must be made such that it can fit into the same size compartments and openings as conventional single size cartridge loading devices.